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AGE

, 37:43 | Cite as

Environmental heat exposure and cognitive performance in older adults: a controlled trial

  • Beatriz Maria Trezza
  • Daniel Apolinario
  • Rafaela Sanchez de Oliveira
  • Alexandre Leopold Busse
  • Fábio Luiz Teixeira Gonçalves
  • Paulo Hilário Nascimento Saldiva
  • Wilson Jacob-Filho
Article

Abstract

Thermal stress has a negative effect on the cognitive performance of military personnel and industry workers exposed to extreme environments. However, no studies have investigated the effects of environmental thermal stress on the cognitive functions of older adults. We carried out a controlled trial with 68 healthy older adults (mean age 73.3 years, 69 % female), each of whom has been assessed twice on the same day with selected tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Repeated sessions were conducted with air temperatures set at 24 °C and 32 °C in a balanced order. Our primary analyses did not show significant differences when comparing the cognitive performance of the total sample under the two experimental temperatures. However, interaction analysis has shown that humidity levels modify the effect of temperature on cognitive outcomes. The subgroup exposed to relative humidity greater than the median value (57.8 %) presented worse cognitive performance in the heat session when compared to the control session. Reported exercising frequency explained individual vulnerability to heat stress. Volunteers with lower levels of physical activity (<4 times per week) were more likely to present worsened cognitive performance under heat stress. In a fully adjusted linear regression model, the performance under heat stress remained associated with relative humidity (β = −0.21; p = 0.007) and frequency of exercising (β = 0.18; p = 0.020). Our results indicate that heat stress may have detrimental effects on the cognitive functioning of some subgroups of older adults and under particular circumstances. Further research is needed for exploring a variety of potentially influential factors.

Keywords

Environmental exposure Hot temperature Heat stress Cognitive manifestations Neuropsychological test Aged 

Notes

Disclosure

The authors declare that they have no competing interests.

Funding

This study received financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP; grant number 2008-57717-6) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; grant number 573813/2008-6).

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Copyright information

© American Aging Association 2015

Authors and Affiliations

  • Beatriz Maria Trezza
    • 1
  • Daniel Apolinario
    • 1
  • Rafaela Sanchez de Oliveira
    • 1
  • Alexandre Leopold Busse
    • 1
  • Fábio Luiz Teixeira Gonçalves
    • 2
  • Paulo Hilário Nascimento Saldiva
    • 3
  • Wilson Jacob-Filho
    • 1
  1. 1.Division of Geriatrics, Department of Internal MedicineUniversity of São Paulo Medical SchoolSão PauloBrazil
  2. 2.Institute of Astronomy, Geophysics, and Atmospheric SciencesUniversity of São PauloSão PauloBrasil
  3. 3.Department of Pathology, College of MedicineUniversity of São PauloSão PauloBrazil

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